The present invention is directed to a machine for automatically removing skin from meat, poultry and fish products.
Automatic skinning machines adapted to remove skin or membrane from meat, poultry or fish products have long been in existence. These skinning machines typically include a frame structure. The frame structure includes a product-supporting surface and an elongated blade mounted over a gripping roller have a plurality of teeth. The blade is held to a shoe means by a blade-holding structure. The shoe has an interior arcuate surface which is complementary in shape to the outer periphery of the teeth of the gripping roller. The blade extends outwardly beyond the blade holder generally above the gripping roller such that a small space exists between the blade and the roller. As the product is moved against the blade, the skin of the product is, severed therefrom and is passed between the gripping roller and the shoe. The skinned product passes above and over the blade. Having only a blade with a sharpened edge often results in damage to products skinned. More specifically, some products have a "silver skin" or membrane positioned between the skin layer and the muscle. It is preferable for this membrane to remain on the muscle for consumer sales purposes. If skin is missing along one portion of the product, the sharp blade will slice through the membrane, thus decreasing the value of the product. Additionally, oftentimes a sharp blade will result in skin being left on a product if the product has a large number of deformities. More specifically, if there are upward undulations within the product, the sharp blade, will tend to slice through the skin as opposed to pulling the skin from the muscle. Thus, skin can remain on areas of the product after it has been passed through the skinning machine.
In order to overcome some of the problems discussed above, efforts have been made in the past to dull the sharpened cutting edge of the blade. As this is done, a pinch point is created between the gripping roller and the front edge of the blade so that the skin is generally pulled from the muscle instead of being sliced from the muscle. This sometimes proves acceptable in removing skin while leaving the thin membrane or "silver skin" mentioned above, and also can allow better removal of the skin from the product.
Problems, however, are associated with having a dull cutting blade. More specifically, in some types of products, such as chicken and turkey, there are sinuous fibers or tissues connecting the skin to the muscle. This connective tissue is very sinewy and tends to maintain its attachment to both the skin and muscle as the skin is being pulled off the muscle. Thus, the fibers of the connective tissue oftentimes will still be attached to the product on top of the cutting shoe and to the skin being conveyed between the gripping roller and the cutting shoe. As is apparent, these fibers can cause clogging between the cutting shoe and the gripping roller and, thus, drastically decrease the efficiency of the automatic skinning machine.
Other problems with prior automatic skinning machines revolve around the possibility of contamination resulting from structures used to attach the cutting blade to the cutting shoe. More specifically, the blade-holding devices of current skinning machines often have apertures opening to the top surface which align with apertures in the cutting shoe. The cutting blade is clamped between the blade-holding plate and the cutting shoe and is held in position by pins or bolts which extend from the top surface of the holding plate through the apertures therein and into the apertures within the shoe. As is apparent, because the apertures in the holding plate extend to the top surface of the plate and product passes over the top surface of the plate, it is inherent that meat particles may accumulate in the crevices and cracks formed by these upper exposed apertures. As this happens and meat particles begin to decay therein, contamination of subsequent product passing over the blade-holding plate becomes inevitable.
Other problems associated with prior art skinning machines pertain to the adjustment of the clearance between the cutting blade and the gripping roller and to allowing the cutting shoe to move in response to oversized portions of skin passing between the gripping roller and the cutting shoe. Current skinning technology utilizes machine spacers or cartridges to adjust the clearance between the blade and the gripping wheel. These types of structures make fine adjustment difficult and time-consuming. Further, these structures do not allow the blade relationship to be easily and accurately adjusted to accommodate different skinning applications and varying s;kin thickness. Still further, prior art structures do not adequately prevent clogging in the space between the gripping roller and the cutting shoe. More specifically, current automatic skinning machines use coil springs to supply downward pressure to the cutting shoe. The resulting pressure vector applied to the cutting shoe is directed in a downward linear plane. Therefore, as a larger piece of skin passes through one side of the elongated cutting blade between the cutting shoe and the gripping roller, the entire cutting shoe assembly raises along its entire width, thus creating problems with the other end of the cutting blade where skin of normal thickness is being removed. As is apparent, this can result in inefficient and ineffective skinning of product.
Additionally, it is often difficult to skin products having a thick skin in current automatic skinning machines. More specifically, it is difficult when the product first engages the blade and cutting shoe for the thick skin to be grabbed or pinched between the blade and the gripping roller. This can result in the product only being partially skinned, or, if the skin is never pinched between the shoe and the gripping roller, the product not being skinned at all.
Additional problems relating to prior art skinning machines revolved around the necessity of cleaning between the gripping roller and the cutting shoe. In such prior machines, the shoe is often separated entirely from the framework of the machine to clean these, areas. Every time this is done, it is necessary to reposition the shoe and blade in the exact desired skinning location above the gripping wheel. As is apparent, oftentimes the exact repositioning of the blade is not accomplished, and if it is accomplished, it requires a great amount of time and effort on the part of the machine user.
Current technology for automatic skinning machines utilizes a plurality of feed rollers mounted on a single shaft at a location that is generally above the cutting shoe and the gripping roller. These driven rollers serve to help propel the product across the blade. Mere specifically, they engage the upper surface of the product while the lower surface of the product is skinned. These rollers are mounted on a single shaft are also supported by a spring-loaded frame so that the rollers move as a single unit. If there are a plurality of products moving under the bank of rollers at the same time, the rollers are at the height of the thickest product. Thus, some of the smaller products may not be adequately propelled across the cutting shoe. Further, oftentimes the single bank of rollers does not adequately discharge the product from on top of the cutting shoe. Thus, product may be stuck directly behind the cutting shoe and on the other side of the feed rollers. The only way this product is moved forwardly is when other product pushes it forward as it is propelled across the cutting shoe and the feed roller. As is apparent, this is not a very effective way of moving product through a device and oftentimes results in clogging or jamming of the machine.
Cleaning of the gripping roller associated with the cutting shoe is also a major concern in automatic skinning machines. Prior structures used to clean such rollers involve a moving spindle on a threaded rod, such spindle having an air nozzle associated therewith. As the rod is rotated, the spindle moves back and forth along the rod, thus directing a jet of air back and forth along the gripping roller to attempt to remove skin and other particles therefrom. This type of cleaning system involves complex moving parts and oftentimes has to be repaired due to clogging or part failure.
Therefore, a skinning machine is needed which alleviates the disadvantages and drawbacks of prior art skinning machines discussed above.